Redis Expiration Policy

One, the Redis key has six kinds of expiration policy

1. Noeviction: Returns error once memory is full

2, ALLKEYS-LRU: All the key to the LRU

3, VOLATILE-LRU: only to set the expired key for LRU (the default way)

4, Allkeys-random: Randomly remove a key

5, Volatile-random: To set the expiration of the key to random culling a

6, Volatile-ttl: Delete the expiring key

According to the official website, the LRU used by Redis is not a real LRU algorithm, and the accuracy is not high. The redis3.0 version of LRU will maintain a candidate pool, which will perform better.

ii. settings and viewing of some memory and expiration policies

1, set the memory size of the instance (local execution can not use-h $host, the unit is B)

Redis-cli-h $host-P $port config set maxmemory 1024

2. Get the memory size of the instance

Redis-cli-h $host-P $port config get maxmemory

3. Set Expiration policy

Redis-cli-h $host-P $port config set maxmemory-policy volatile-lru

4. View Expiration policy

Redis-cli-h $host-P $port config get maxmemory-policy

Description: After testing the Volatile-lru, it is true that if there is a key that has an expiration time set, the LRU will be executed and the insertion can continue. If you don't have a key with expiration time set, you will get an error.

Redis Expiration Policy